Smart Engine guys! How/why did this happen?

[hammbone]

The 2006 23' LSV has 506 hours on it and the engine is junk!

During a cruise back to the beach I noticed a slight decrease in power. Long story short #5 exhaust value has a pie shaped chunk out of it resulting in no compression. Things got worst fast when we got the head off. Some water jackets were plugged solid near the middle cylinders. Basically the engine had extreme hot spots due to plugged cooling paths. Pistons/cylinder walls were junk. Time for a new engine.

My big question is what caused this white chalk like substance to stick in primarily the hot spots in the engine. Outer areas aren't as bad.

Some notes:

1. I bought the boat used. It was one year old and used as a wakeboard camp boat in the California Delta. I suspect it was not pulled out off the water most of the summer. It had 180 hours on it when I bought it.

2. The first 2 years I was in pretty clean fresh water then last summer we started going to Pyramid Lake.http://en.wikipedia....d_Lake_(Nevada)

3. The salinity is approximately 1/6th that of sea water

4. I flushed the motor using a fake-a-lake after every run in Pyramid.

I know several boat owners that spend much more time at Pyramid and don't flush the boat until the end of summer. One is going on 8 yrs. another 10 years.

Is this a bad combo of the Delta and Pyramid creating a reaction?

I'm open to ideas and thanks for the help!

[JeffS]

I know several boat owners that spend much more time at Pyramid and don't flush the boat until the end of summer. One is going on 8 yrs. another 10 years.

Is this a bad combo of the Delta and Pyramid creating a reaction?

I'm open to ideas and thanks for the help!

I only know 7 things, and this isn't one of them. But this doesn't appear to be salt or corrosion. I've seen engines eaten by salt. The weak point is the exhaust manifolds. I'm a big-boat cruiser/yacht guy, and I know a raw-water-cooled saltwater engine on the inside when I see one - and that doesn't look like the symptoms.

The white chalky substance looks like a dissimilar metal reaction (aluminum head on an iron block) kind of corrosion deposit. Like I said, I don't know much, and know absolutely nothing about your engine or what it's made of. So I don't know if that's helpful at all. If it is an aluminum head on an iron block, with a lot of stray current in the water, near a boat that is left wet slipped for a long time, and ineffective sacrificial anode corrosion protection through the shaft and on to the motor, you could get that chalky corrosion on areas where dissimilars metals touch.

All I'm hoping you get from this post - it looks like your care of the engine after runs on Pyramid were effective. I don't think you did this to your motor by NOT doing something, or taking the boat in brackish water. I think something went very wrong early on, and it got worse and worse until you melted a valve.

I'll be watching the thread. I'm sorry for your situation and am interested to know learn from others here as well.

Edited July 21, 2010 by JeffS

[hammbone]

I only know 7 things, and this isn't one of them. But this doesn't appear to be salt or corrosion. I've seen engines eaten by salt. The weak point is the exhaust manifolds. I'm a big-boat cruiser/yacht guy, and I know a raw-water-cooled saltwater engine on the inside when I see one - and that doesn't look like the symptoms.

The white chalky substance looks like a dissimilar metal reaction (aluminum head on an iron block) kind of corrosion deposit. Like I said, I don't know much, and know absolutely nothing about your engine or what it's made of. So I don't know if that's helpful at all. If it is an aluminum head on an iron block, with a lot of stray current in the water, near a boat that is left wet slipped for a long time, and ineffective sacrificial anode corrosion protection through the shaft and on to the motor, you could get that chalky corrosion on areas where dissimilars metals touch.

All I'm hoping you get from this post - it looks like your care of the engine after runs on Pyramid were effective. I don't think you did this to your motor by NOT doing something, or taking the boat in brackish water. I think something went very wrong early on, and it got worse and worse until you melted a valve.

I'll be watching the thread. I'm sorry for your situation and am interested to know learn from others here as well.

Thanks for the ideas. The heads are iron.

[areamike]

Might as well upgrade to the 383 while you got it all apart.

[shawndoggy]

I wish I had something helpful to add.

As far as I know, the Delta is all fresh water... at least where it would be flat enough to wakeboard.

But man, you're definitely making me paranoid about heading to pyramid next month once Lahontan is dried up.

[areamike]

I wish I had something helpful to add.

As far as I know, the Delta is all fresh water... at least where it would be flat enough to wakeboard.

But man, you're definitely making me paranoid about heading to pyramid next month once Lahontan is dried up.

I wouldn't worry too much as long as you flush you motor afterward with fresh water. Like a previous poster said, it most likely was a preexisting condition when the OP bought the boat that progressively got worse.

[68Slalom]

There is a galvanic reaction that occurs with marine engines and there is usually a zinc rich material anode that is placed on outboards that intercepts that current field. Inboards don't have that because the only thing really out is the prop and shaft but really have no other protection from this. I have heard of people actually filling up the engine blocks with anti-freeze during the winter that helps prevent this. You can use bio-degradable products but they don't work as well, what usually goes first is a head gasket from this type of corrosion.

One other indicator that could have been a warning sign, is by pulling your plugs every year, you would have noticed that those two cylinders were running lean due to the temperatures and the plugs would have been white. All this is too late but little things to keep in mind, I usually winterize by boats every year and pull plugs to spray each cylinder out with a fogger and that is usually when I inspect each one.

[Sixball]

The pitting on the piston indicates preignition. Do any of the other pistons show pitting? If not I would have a close look at the injector for the cylinder in question. Its hard to tell but it looks like the head gasket was sealed.

[CumminsBu]

Have you tested the thermostat? A theory I have is your flush may not have been long enought with the thermostat open to cirulate the old lake water to flush water through the block and head. Other then my boat I have worked on mostly water jacketed marine engines where raw water flows through a cooler.

[areamike]

The pitting on the piston indicates preignition. Do any of the other pistons show pitting? If not I would have a close look at the injector for the cylinder in question. Its hard to tell but it looks like the head gasket was sealed.

[hammbone]

Might as well upgrade to the 383 while you got it all apart.

Thought of sumin' like that but imdmar won't release the software to mod the tuning.

[hammbone]

One other indicator that could have been a warning sign, is by pulling your plugs every year, you would have noticed that those two cylinders were running lean due to the temperatures and the plugs would have been white. All this is too late but little things to keep in mind, I usually winterize by boats every year and pull plugs to spray each cylinder out with a fogger and that is usually when I inspect each one.

The plugs oddly enough were not that bad. They didn't look as they were running lean. It was the first thing we went after at the lake.

[hammbone]

Have you tested the thermostat? A theory I have is your flush may not have been long enought with the thermostat open to cirulate the old lake water to flush water through the block and head. Other then my boat I have worked on mostly water jacketed marine engines where raw water flows through a cooler.

I've run the motor up to 160 then run another 10mins. from then. Maybe not long enough???

[hammbone]

I agree and I did change out the injector in case, but the thing that bothers me is the #3 adjacent cyn was overheated also. Not as bad as #5 but certainly not right! Which leads us to point back at the cooling water flow problem. Flip'n head scratcher...

The good news is I got the new motor lit up today and no problems! Runs very smooth.

[areamike]

I agree and I did change out the injector in case, but the thing that bothers me is the #3 adjacent cyn was overheated also. Not as bad as #5 but certainly not right! Which leads us to point back at the cooling water flow problem. Flip'n head scratcher...

The good news is I got the new motor lit up today and no problems! Runs very smooth.

Did you at least check the injectors to make sure they were not clogged?

[Sixball]

Are you doing the tare down? More pictures get the top of the block. It looks like the cylinder is very out of round it must have been hot? Get a shot of the piston and skirt also.

[dlll]

the scoring indicates the cylinder got hot. intern burning the valve maybe the pic i cant see seams the side of the piston is also gone indicates that it got hot possible injector running lean but the cylinder dose not look lean it would be dry and a whiteish in color. I would ohm the injectors out to see if that one is bad. If i remember right the ohms should be no more than .065 but dont quote me on that i would have to look in my Alldata for sure. if you had a timing issue or pinging all the pistons would show some signs but only that one. intake leak? either way its engine time

Edited July 23, 2010 by dlll

[hammbone]

I think we got off my main question here...

What is the white crud in the water jackets?

There's not much doubt the thing got real hot and it sure looks like it's from lack of cooling due to the plugged water jackets. The problem is I don't know what casued it? 506 hours isn't that much time.

[Sixball]

It is very hard to see or tell much other than it is there. Is it crusty, greasy, jelly,Hard, any info may help.

Do you know if a stop leak has been used? It does look as it could be a big contributer. What did the oil look like?

The valve did not melt it shattered from detonation I am betting.

[99response]

Looks like mineral deposits from the water.

May be a decent time to throw in a closed cooling system so you never have to worry about it again.

-Chris

[hammbone]

It is very hard to see or tell much other than it is there. Is it crusty, greasy, jelly,Hard, any info may help.

Do you know if a stop leak has been used? It does look as it could be a big contributer. What did the oil look like?

The valve did not melt it shattered from detonation I am betting.

The white stuff was similar to ground chalk, soft mush between your fingers. It was easy to ream out the holes with a small screw driver. Nothing like the stuff on say a house water faucet. Pure white.

Stop leak is an interesting thought. Though does that stuff work on a non-pressurized system? Not to say someone may have tried anyway.

If the accent cylinder wasn't looking cooked also I would be more suspect of a fuel problem like an injector also. Plugs looked fine. From what I've heard if the jug was running lean it should be burned up also. We couldn't tell any of them apart. All the plugs looked very similar.

When I think about when the valve let go it was after turning about 3500-4000 rpm for about 10mins. Thinking the hot spots got real good and hot! Maybe hot enough to cause pre-detonation blow'n a very hot valve??????

Thanks again for the thoughts guys!

[68Slalom]

Is that white corrosion all throughout the entire cooling system, hoses, water pump, etc? If so, this may be something other people can check for as an indicator!

[CumminsBu]

Maybe a kid put some side walk chalk or candy in your water pickup. Do you have a water shut off valve, could be pipe dope or Liquid Teflon.

Edited July 24, 2010 by CumminsBu

[hammbone]

Maybe a kid put some side walk chalk or candy in your water pickup. Do you have a water shut off valve, could be pipe dope or Liquid Teflon.

Looks like you've met my two boys then

Nah too much materiel to be pipe dope.

[hammbone]

Here's the reply I received from Indmar Service:

Sorry you have experienced this problem. At first the white deposits looked like the kind of corrosion we see on an engine with aluminum cylinder heads but your engine does not have aluminum heads. We have seen some similar deposits on engines that run in lakes that have high mineral content. When the water drains out of the block it leaves behind a very thin layer of these mineral deposits that adhere to the insides of the cooling passages and reduce the ability of the water to remove heat from the engine ... especially in the cylinder heads because of the heat generated there. Over time, little by little these deposits build up and may cause blockages ... kind of like mineral deposit build up in a coffee maker. The heads are also more susceptible because the water generally drains out of them when the engine is stopped leaving these minerals exposed to air and heat which cause them to get harder. The only 100% way to avoid this is to use a closed cooling system that runs anti-freeze through the engine instead of raw water. There may be some chemical flushing additives available that might help dissolve the deposits. Using a 140 degree thermostat instead of 160 might help also as the heads will run cooler and heve less of a tendency to let the deposits build up and harden. This of course is only based on what I see in the photos. Without actually touching the heads and doing a thorough inspection this is only my best guess.